Heat-resistant nylon cloth produced by reaction with quinones



Patented May 20, 1952 HEAT-RESISTANT I NYLON CLOTH PRO- DUCED BYREACTION WITH QUINONES Edwin B. Michaels, Stamford, Conn., and SamuelMachlis, New Rochelle, N. Y.

No Drawing. Application November 25, 1949, Serial No. 129,526

3 Claims. 1

This invention relates to new and useful improvements in the treatmentof nylon and especially nylon cloth to make it heat resistant andadapted for use as a pressing cloth cover for steam heated laundrypresses.

This invention is applicable to nylon cloth whether the fill and warpare formed entirely of monofilament threads or whether the fill isformed of spun staple nylon, and the warp threads are formed ofmonofilament threads.

Woven nylon cloth'has a very high tenacity and abrasion resistance. Ithas been found that cloth woven from nylon thread where the fill is spunfrom staple nylon and the warp from monofilaments, has tougher abrasionresistance than cloth consisting of warp and fill formed of monofilamentthreads even when they are of high denier. This adapts the nylon clothfor use as a cover for laundry presses. However, in spite of verydesirable initial qualities, this cloth has been found to rapidlydisintegrate at temperature above 300 F. and particularly when theclothing being treated contain starch.

It is known that untreated nylon cloth may lose as much as 70% of itsstrength in five hours when subjected to an ironing temperature of 180C. (356 F.). The same cloth in hours may lose over 90% of its originaltensile strength. It has been found that the heat deterioration of nylonis dependent largely upon an oxidation reaction accelerated by hightemperatures. The main object of the present invention is to block thisoxidation reaction and thereby check or reverse this degenerativecharacteristic of nylon under heat.

It has been found that spun nylon yarn deteriorates much more rapidlythan monofilament yarn. However, when treated in accordance with thisinvention, these finer filaments no longer experience rapiddeterioration and this makes possible the production of resistantfabrics woven from spun yarns. This is of great importance because spunyarns have a significantly higher abrasion resistance than themonofilament yarn.

A further object is to provide a very simple and eificient method forthe relatively inexpensive treatment of nylon cloth to produce in itsuch a resistance to heat as will greatly increase its utility for anyuse in which it may be subjected to temperatures above 300 F., but notexceeding the melting point of the nylon.

It has been found that this improved condition of the cloth or materialcan be achieved by combining with the nylon certain quinones of whichbenzoquinone is an example. Another quinone which may be used isanthraquinone. This treatment is most'readily and eflicientlyaccomplished by immersing the cloth in an aqueous solution ofbenzoquinone. The immersion may be made of various samples of cloth insolution of 0.5% to 5%, and pH below '7, for periods of time rangingfrom 12 seconds to 24 hours, and at temperatures ranging from 15 to 100C. The percentage of solution, the time period and the temperaturesemployed would depend upon the characteristics of the material beingtreated. It has been found further that the most effective treatment asa whole has been effected by use of 1% solutions of benzoquinone inwater at room temperatures for about 15 hours.

As an example, 15 yards of 44 inch nylon cloth (Whitehouse LeatherProducts #8,400 monofilament warp and spun fill), is immersed in a bathprepared by dissolving 160 grams of benzoquinone in 16 liters of water.The cloth is emerged for 15 hours at F., and after treatment, is rinsedfree of the quinone and dried ready for use. Cloth so treated may loseabout 25% of its tensile strength when heated for 15 hours at 350 F.,whereas the untreated cloth will lose 70% of its strength in five hoursat the same temperature and of its strength in 15 hours at the sametemperature.

The process may be considerably speeded up by the use of increasedtemperatures and in commercial production for example, pounds of nylonfabric treated in a solution consisting of approximately 5 pounds ofbenzoquinone in 200 gallons of water at F. for two hours underagitation, produces a satisfactory product with an increase of tensilestrength of about 10% or better. In this process, the cloth can be keptmoving in the water to prevent a settling of the benzoquinone in thesolution. In preparing the solution, it has been found that a morestable solution can be secured if the benzoquinone is first dissolved inacetone or di-acetone and the water added. However, this method whileproducing a more stable solution has certain disadvantages in that gashaving an unpleasant odor, is released and for this reason, it has beenfound more satisfactory to prepare the solution by adding steam orboiling water to the powdered chemical.

It has been found that a cloth so treated is impervious to anydegenerative effects from starch in the clothing being pressed thereon.Any untreated nylon will gradually coat with starch when used as anironing cloth, as it is adhesive to the starch. Nylon processed inaccordance with the present invention, is non-adhesive to starch andwill not coat. It has also been found that other quinonoid bodies suchas the oxidation products of pyrogallic acid, may be used and willresult in a marked increase of the resistance of the nylon cloth to heatdegradation.

It is, of course, expressly understood that the nylon cloth impregnatedin accordance with the invention is a water insoluble nylon cloth formedof a polyamide having the general formula (.NH.(CH2) .NH.CO. (CH2)yCO.NH. (CH2) 1:.

where a: and y are integers greater than 1.

While the invention has been described in detail, it is not to belimited to such details and forms since many changes and modificationsmay be made in the invention without departing from the spirit and scopeof the invention in its broadest aspects. Hence, it is intended to coverany and all forms and modifications of the invention which may comewithin the language or scope of any one or more of the appended claims.

What we claim as our invention is:

1. A heat resistant polyamide fabric produced at the process ofimpregnating a Water insoluble polyamide woven cloth in which thepolyamide has the formula [.NH. (CH2) m.NH.CO. (CH2) y-CO.NH.(CH2) r.

where :r and y are integers greater than 1, with a 0.5 %-5% aqueoussolution of a quinone of the class consisting of benzoquinone, andanthraquinone having a pH of less than '7 at a temperature ranging from15 C. to 100C. for a period of time ranging from 12 seconds to 24 hours.

2. A heat resistant polyamide fabric produced by the process ofimpregnating a water insoluble polyamide woven cloth in which thepolyamide has the formula [.NH. (CH2) w.NH.CO. (CH2) .CO.NI-I.(CH2) I..l

where a: and y are integers greater than 1, with a 0.5 %-5% aqueoussolution of benzoquinone having a pH of less than 7 at a temperatureranging from 15 C. to C. for a period of time 7 ranging from 12 secondsto 24 hours.

3. A heat resistant fabric produced by the process of impregnatingv awater insoluble woven cloth in which the polyamide has the formulaREFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,265,119 Coolidge Dec. 2, 19412,312,469 Freund Mar. 2, 1943 2,484,529 Roedel Oct. 11, 1949

1. A HEAT RESISTANT POLYAMIDE FABRIC PRODUCED AT THE PROCESS OFIMPREGNATING A WATER INSOLUBLE POLYAMIDE WOVEN CLOTH IN WHICH THEPOLYAMIDE HAS THE FORMULA